New perspectives on the evolutionary history of hepatitis B virus genotype F.

ABSTRACT

Hepatitis B virus (HBV) is a globally distributed human pathogen. The aim of this work was to analyze the evolutionary history of HBV genotype F, emphasizing on the study of subgenotypes prevalent in the Southern area of South America. Complete genomes of HBV genotype F from 36 samples from Argentina and Chile were sequenced and analyzed by phylogenetic and Bayesian coalescent methods along with sequences obtained from GenBank database. The phylogeography separated not only Central American from South American isolates but also revealed that different subgenotypes are distributed in constrained although not exclusive areas of the continent. The result obtained with time-stamped complete genomes failed to explain the wide geographical distribution and the clustering observed in this genotype. Conversely, the use of Bayesian coalescent analyses with substitution rates as priors, instead of the co-estimation of tMRCA and substitution rate, allowed us to propose a far origin for the HBV genotype F based on the phylogeographical and epidemiological data.